Medical emitter/detector imaging/alignment system and method

ABSTRACT

Improved methods and apparatuses for imaging during medical procedures in accordance with various embodiments of the present invention include use of an image correction algorithm. In various embodiments, an original image of a region of interest where a medical procedure occurring along a particular axis will be performed is created with a beam emitter and a generally planar detector. Due to the emitter not being aligned orthogonal to the detector, the original image will be skewed. Using a known location and orientation of the detector, a location and orientation of the emitter provided by a position monitoring system, and the original image, a processing system can execute the image correction algorithm to provide a corrected image to allow a surgeon to perform the medical procedure while viewing an accurate corrected image in real-time.

RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 61/328,062, filed Apr. 26, 2010, the disclosure of whichis hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to apparatuses and methods for imagingwhile performing medical procedures along a particular alignment. Morespecifically, the present invention relates to imaging systems thatallow accurate imaging of a procedure as it is being performed when analignment axis of an emitter is not orthogonal to a planar detector.

BACKGROUND OF THE INVENTION

Imaging systems are utilized for various applications in the medicalfield as well as non-medical applications. For example, medical imagingsystems include general radiological, mammography, X-ray C-arm,tomosynthesis, ultrasound and computed tomography imaging systems. Theseimaging systems, with their different respective topologies, are used tocreate images or views of a region of a patient.

Modern medical imaging systems have become a valuable tool in thehealthcare profession. Many imaging systems which were once found onlyin major medical facilities have become more commonplace due to theiraffordable cost and compact size. Mobile imaging systems are utilizedoutside of imaging-specific rooms because of their ability to betransported to operating rooms or other areas serving multiple purposes,thus providing instant on-the-spot imaging.

As a result, real-time imaging is increasingly being required by medicalprocedures. For example, many electro-physiologic cardiac procedures,peripheral vascular procedures, percutaneous transluminal catheterangioplasty procedures, urological procedures, and orthopedic proceduresutilize real-time imaging. In addition, modern medical procedures oftenrequire the use of instruments that are inserted into the human body.These medical procedures often require the ability to discern the exactlocation of instruments that are inserted within the human body, oftenin conjunction with an accurate image of the surrounding body throughthe use of imaging.

It would be desirable to provide a directed imaging system designed toreplace existing methods for imaging during medical procedures with afaster and more accurate system in situations where an alignment axis ofan emitter is not orthogonal to a planar detector.

SUMMARY OF THE INVENTION

Improved methods and apparatuses for imaging during medical proceduresin accordance with various embodiments of the present invention includeuse of an image correction algorithm. In various embodiments, anoriginal image of a region of interest where a medical procedureoccurring along a particular axis will be performed is created with abeam emitter and a generally planar detector. Due to the emitter notbeing aligned orthogonal to the detector, the original image will beskewed. Using a known location and orientation of the detector, alocation and orientation of the emitter provided by a positionmonitoring system, and the original image, a processing system canexecute the image correction algorithm to provide a corrected image toallow a surgeon to perform the medical procedure while viewing anaccurate corrected image in real-time.

In one embodiment, a system for performing a medical procedure on apatient utilizes an image correction algorithm. The system can include amanually positionable beam emitter including an actuator for performingthe medical procedure along a particular axis. A generally planardetector can detect the beam from the emitter and generate an originalimage of a region of interest between the emitter and detector. Aposition monitoring system can monitor a position and orientation of theemitter. A processor operably connected to the position monitoringsystem and the detector can execute an image correction algorithmoperable to provide a corrected image from the original image due to theoriginal image being skewed as a result of the emitter being alignedalong the axis of operation rather than perpendicular to the detector. Avideo display can display the corrected image in real-time to a surgeonperforming the medical procedure on the patient.

In another embodiment, a method includes providing a system forperforming a medical procedure on a patient. The system can include amanually positionable beam emitter including an actuator, a generallyplanar detector that detects the beam from the emitter, a positionmonitoring system that monitors a position and orientation of theemitter, a processor that executes an image correction algorithm and avideo display. The method can further include instructions forperforming the medical procedure on the patient. The instructions caninclude manually positioning the emitter in more than three degrees offreedom along an axis of operation of the actuator at an angle that isnot perpendicular to the detector to obtain an original image of aregion of interest, which results in the original image being skewed.The instructions further comprise viewing a corrected image of theregion of interest on the video display that results from application ofthe image-correction algorithm to the skewed original image andperforming the medical procedure with the actuator while utilizing thecorrected image in real-time to assist during the medical procedure.

The above summary of the various embodiments of the invention is notintended to describe each illustrated embodiment or every implementationof the invention. This summary represents a simplified overview ofcertain aspects of the invention to facilitate a basic understanding ofthe invention and is not intended to identify key or critical elementsof the invention or delineate the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 depicts a medical imaging/alignment system according to anembodiment of the present invention.

FIG. 2 depicts a medical imaging/alignment system according to anembodiment of the present invention.

FIG. 3A depicts an imaging emitter gun according to an embodiment of thepresent invention.

FIG. 3B is a cross-sectional view of the imaging emitter gun of FIG. 3A,taken at the midplane of the gun looking into the page.

FIG. 4 depicts a flowchart of steps of an image correction algorithmaccording to an embodiment of the present invention.

FIG. 5A is a view of an object and original and corrected images of theobject according to an embodiment of the present invention.

FIG. 5B is another view of an object and original and corrected imagesof the object according to an embodiment of the present invention.

FIG. 6 depicts the use of an imaging/alignment system according to anembodiment of the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, one skilled in the artwill recognize that the present invention may be practiced without thesespecific details. In other instances, well-known methods, procedures,and components have not been described in detail so as to notunnecessarily obscure aspects of the present invention.

Referring to FIG. 1, a schematic representation of a medicalimaging/alignment system 100 according to an embodiment of the presentinvention is depicted. System 100 generally includes a beam emitter 104and a detector 102 for detecting the beam generated by emitter 104.Emitter 104, as described more fully herein, can also incorporate adrill, cutting tool, needle/syringe or other device for performing amedical operation on a patient. System 100 can also include a positionmonitoring system 106 to keep track of or sense the movements of theemitter 104 in any number of degrees of freedom. A processor executing acomputer-implemented image correction algorithm 108 can be used, asdescribed more fully herein, to provide a more accurate image of theimaged region to a surgeon, who views the corrected image on a monitoror display 110 in real-time.

The detector 102 is placed beneath/opposite the patient in the area ofinterest, i.e., the area where the medical procedure is performed. Inone embodiment, detector 102 is a flat-panel detector mounted beneath apatient table and on an X/Y movable stage allowing it to be positionedunder the area of interest of the patient as needed. Such modernflat-panel detectors are advantageous in that they are light weight, canrun high frame-rates, use fewer parts and can provide an immediatedigital image. Various flat-panel detectors that can be used withembodiments of the present invention are manufactured by Varian MedicalSystems of Palo Alto, Calif.

In one embodiment, detector 102 should provide at least near real-timefeedback to the surgeon. In this embodiment, detector 102 can acquireimages at a frame rate of at least 15 frames per second. It has beenobserved that at rates of higher than 25 frames per second it isdifficult to discern meaningful differences in detected images as aresult of such higher rates, so a range of frame rates of 15 frames persecond to 25 frames per second is preferred. Ideally, the system 100uses the largest flat-panel detector 102 that can provide such aresponse time in the desired range of frame rates. In one embodiment,such response times can be provided by a 16″ by 12″ detector 102.

The emitter 104 can be a handheld emitter gun that can include animaging source located behind an actuator for performing a medicalprocedure on a patient. Actuator can include, for example, a drill bitand drive assembly, a cutting tool or cutting blade, a needle or syringeor any other device for performing a medical procedure. In oneembodiment, some or all of the elements of the actuator are translucentto the beam of the imaging source so as not to interfere with theemitted beam. In this embodiment, at least the portion of the actuatorthat is coaxial with an axis of emission of the emitter is translucent.This provides an unobstructed image as the procedure is performed, whichallows the surgeon to image the target at the same time as performingthe procedure without the need for a separate device. One embodiment ofan X-ray translucent drill mechanism, aspects of which can be used inembodiments of the present invention, is disclosed in U.S. Pat. No.5,013,317 to Cole et al., which is incorporated herein by reference. Inanother embodiment, the imaging source can be aligned along a parallelaxis to the axis of operation of the medical procedure so that theactuator does not interfere with the emitted beam while still beingaligned at the same angle.

An emitter 104 in the form of a handheld gun according to an embodimentof the present invention is depicted in FIGS. 3A and 3B. Gun 104 islightweight and easily maneuverable by a surgeon and includes a handle115 connected to a housing 116. Housing contains the actuator 118, whichas noted above can be translucent to the beam, and an imaging source. Inone embodiment, the source is positioned behind the actuator 118 in thehousing. In one embodiment, actuator 118 is a drill mechanism. Drillmechanism 118 can be provided with variously sized interchangeable drillbits 120 to form pilot holes prior to inserting screws. Drill mechanism118 can also directly insert screws into a desired area. As noted above,gun 104 can include various other actuators other than drill mechanism.In some embodiments, gun 104 can be about the size of a modern cordlessdrill, allowing the surgeon to move about freely with the device whileperforming the procedure. In some embodiments, the actuator 118 can beinterchangeable, such that a diverse range of procedures can beperformed utilizing the same general system. In one embodiment, this canbe done by allowing the actuator 118 to be removed from the housing 116and replaced with a different actuator 118. In another embodiment, aplurality of emitter/guns 104 can be provided that can be interchangedwithin the general system 100, each pre-configured with a different typeof actuator 118 and/or a different type of imaging source. In oneembodiment, the emitter can be provided with a safety feature that onlyallows a beam to be emitted when it is aimed at the detector, to preventunnecessary and potentially harmful emission of beams.

A position monitoring system 106 is used in system 100 because propervisualization of the procedure requires knowing where the emitter 104 ispositioned and oriented in space. In some embodiments, the detector 102does not need to be tracked by the position monitoring system 106because it maintains a fixed orientation in space after initially beingset for the procedure, so its location and orientation are known. Inother embodiments, the surgeon can adjust the detector 102 during theprocedure, so the location and orientation of the detector 102 can alsobe monitored.

Position monitoring system 106 must be compatible with the nearbyimaging source, tolerant of significant metal in the environment, andhave high reliability and accuracy. In some embodiments, positionmonitoring system 106 can be an optical tracking system, such asmanufactured by Ascension Technology Corporation of Milton, Vt. In otherembodiments, position monitoring system 106 can be akinematic/mechanical tracking via an arm or linkage. In such anembodiment, the emitter/gun can be attached to a manually positionablearm anchored to a ceiling, wall or floor of an operating room or amovable base in the operating room. In other embodiments, positionmonitoring system can use radio-frequency identification, image analysisusing infrared light or other wireless tracking/sensing. In someembodiments, some or all of position monitoring system 106 can beincorporated into emitter 104 rather than being a separate system. Insuch embodiments, position monitoring system 106 can use one or more ofaccelerometers, gravitometers, magnetometers, and global positioningsystems to track and/or sense the location and orientation of emitter104. Position monitoring system 106 can allow the emitter to bepositionable, and track the positioning of the emitter, in at leastthree degrees of freedom. In some embodiments, the emitter can bepositionable in five or six degrees of freedom. In one embodiment,emitter can be lockable to prevent movement in one or more degrees offreedom for all or part of the procedure, such as only allowing theemitter to be moved along the axis of operation once proper alignmenthas been obtained.

Tracking the emitter's 104 location and orientation relative to thedetector 102 and imaged area allows the use of a perspective imagecorrection algorithm to eliminate the need to keep the gun 104perpendicular to the detector 102, giving the surgeon a great deal offreedom of movement in performing the procedure. This is desirablebecause often a required axis or alignment of the procedure relative tothe patient's body is not aligned perpendicular to the detector. If theprocedure requires the emitter 104 to be aligned relative to the patientin a way that causes it to be at angle to the detector 102, a skewedimage is detected and generated by the detector. Use of an imagecorrection algorithm allows the surgeon to align the gun 104 at an angleto the detector 102 that is properly aligned with the patient forperforming the procedure while visualizing an accurate image of thetarget area of the patient.

The image correction algorithm 108 therefore allows the emitter 104 tobe used in alignments that are not orthogonal to the detector 102 whenthe emitter 104 is being used to image the area of interest 112 of apatient on a patient table 114, as depicted in FIG. 2. The skewed imageresulting from non-orthogonal alignment of the emitter 104 and detector102 can result in misalignment of the actuator for the procedure. Theimage correction algorithm 108 corrects this skewed image so that a trueimage is shown to the surgeon in real time, allowing for more accurateuse of the gun 104 during the procedure. It should also be noted, as canbe seen in FIG. 2, that the thickness of the table 114 combined with thethickness of the patient 112 places a geometric limit on the angle atwhich the emitter 104 can be used relative to the area of interest 112in order to be captured by the detector 102.

In one embodiment as shown in FIG. 4, the image correction algorithm108, which can be executed by a processor, operates directly on thetexture coordinates of the original image recorded by the detector 102using matrix transforms. Transform matrices are a consistent way ofrepresenting linear transforms in a computational format. Byrepresenting object locations as vectors, e.g., f=(x, y, z), thoseobjects may be transformed in space (to f) by multiplying them with atransform matrix T such that f′=Tf. If the detector 108 dimensions andit's transform in space D are known, the location of the four corners ofthe detector 102 can be defined with these methods at step 140 in asingle 4×4 matrix C, where x1, y1 and z1 (obtained from D and detector102 geometry) are a first corner of the detector 102 and so on up to x4,y4 and z4. The fourth element of each corner's vector represents thescale of each vector, which may be set to 1.

$C = \begin{bmatrix}{x\; 1} & {x\; 2} & {x\; 3} & {x\; 4} \\{y\; 1} & {y\; 2} & {y\; 3} & {y\; 4} \\{z\; 1} & {z\; 2} & {z\; 3} & {z\; 4} \\1 & 1 & 1 & 1\end{bmatrix}$

Standard texture coordinates ranging from 0 to 1 can then be assigned tothe four corner points at step 142. Texture coordinates (or UVcoordinates) are a tool used to linearly map a two-dimensional imageonto a three-dimensional object in space. These coordinates, usuallyrepresented as u and v, are assigned across an image, ranging from 0 to1 in each direction. Each vertex of the three-dimensional object isassigned a u and v coordinate indicating which part of thetwo-dimensional image is associated with that vertex. Since the detectorplate is rectangular and is covered by the detected image, the fourcorners (or vertices) of the detector map correspond to the four cornersof the detected image. These four texture coordinates are packed into atexture matrix T.

$T = \begin{bmatrix}0 & 1 & 1 & 0 \\0 & 0 & 1 & 1\end{bmatrix}$

By treating the emitter 104 as something of an imaginary camera, aperspective transformation for the field of view (“fov”) onto thedetector 102 can be defined using a standard perspective transformmatrix at step 144. Preferably, the fov is computed to be just largeenough to view the whole detector plate from the emitter's location. Inmost applications, a field of view of 45 degrees is sufficient. Aperspective transform matrix alters the shape of a given geometry tomatch the view of that geometry from a defined location. It addsperspective to the resulting image, such as by causing portions of thegeometry that are further away to be smaller. This mimics the view aswould be seen by the human eye from the defined location.

$P = \begin{bmatrix}\frac{1}{h} & 0 & 0 & 0 \\0 & \frac{1}{h} & 0 & 0 \\0 & 0 & \frac{\left( {{far} + {near}} \right)}{\left( {{near} - {far}} \right)} & \frac{\left( {2\mspace{14mu} {far}\mspace{14mu} {near}} \right)}{\left( {{near} - {far}} \right)} \\0 & 0 & {- 1} & 0\end{bmatrix}$

Where h=tan(fov/2) and far and near are the distances to the far andnear view planes. For optimal viewing, near is set at 1 and far is thedistance between the emitter 104 and the furthest corner of the detector102. Next, the gun/emitter transform matrix G (obtained from theposition monitoring system) can be used to bring the detector 102corners into the image of the imaginary camera, C*, at step 146.

C*=PGC

Finally, the corrected image is obtained at step 148 by rasterizing theimage space corners C* as a quadrilateral textured with the originaldetector image, by interpolating according to the texture coordinates.Rasterization is a standard computer graphics algorithm, which is knownto those skilled in the art. Rasterization, also known as scanconversion, is the process of rendering a three-dimensional shape orscene onto a flat two-dimensional surface, usually so it can be viewedon a monitor. Rasterization is used as part of the image correctionalgorithm 108 to render the transformed detector plate object (texturedwith its detected image) into the view space of the imaginary cameralocated at the gun/emitter. This yields the corrected image. In oneembodiment, the image correction algorithm is performed by a desktop orlaptop computer. In other embodiments, the algorithm can be performed bya processor within the emitter 104 or detector 102 or associated withthe monitor or display 110. In one embodiment, the algorithmcontinuously runs during the operation to provide a continuous real-timecorrected image that continually adjusts for movements of the emitter104, detector 102 or region of interest to show the actual appearance ofthe region in real-time.

CorrectedImage=Rasterize(C*,T,OriginalImage)

By defining the field of view and near/far planes as described herein, aminimum of information is lost during the image correction process. Noscaling is required to obtain a properly sized corrected image. Theentire process can also be implemented using modern graphics hardware.Corrected images can therefore be processed at extremely high framerates on the order of hundreds of times per second even for largeimages.

FIGS. 5A and 5B depict results of such image corrections. In FIG. 5A, acylindrical object 130 is being viewed with the beam emitter 104 alongthe vertical axis of the object. On the left the original image 132result as initially detected by the detector 102 is displayed. Becauseof the angle between the emitter 104 and the detector 102, the image 132is skewed. The corrected image 134 as displayed on a monitor 110following application of the image correction algorithm 108 describedherein to the image 132 recorded at the detector, which as can be seenis identical to the actual image 130, is displayed on the right. FIG. 5Bdepicts a view of a cylindrical object 130 from an oblique angle withthe emitter 104. Similarly, the original image 136 as detected by thedetector 102 is skewed, whereas the corrected image 138 displays theactual appearance of the object 130 from the oblique angle.

Referring now to FIG. 6, there can seen the result of such an imagecorrection during a procedure being performed on a patient 113 on apatient table 114 according to an embodiment of the present invention.The view in the Figure is taken down the emitting axis of an emitter atan angle to the detector. The original skewed image 152 generated by thedetector is corrected with the processor operating the image-correctionalgorithm and is displayed as a corrected image 154 that shows theactual appearance 150 of the patient's spine from the angle on themonitor 110.

The monitor 110 need only be safe for use in an operating room and largeenough to be easily observed by a surgeon while performing an operation.The monitor must be sterile if located within the sterile field of theprocedure. If the monitor is not within the sterile field, it will nothave to be sterile but will have to be larger than a monitor within thesterile field in order to be viewable from within the sterile field. Inone embodiment, the display can be part of the emitter gun, such as avideo screen located on a proximal end of the gun.

Beam emitter 104 and detector 102 can incorporate various imagingsystems that can be employed in embodiments of the above describedsystem 100. Beam emitter 104 and detector 102 can relate to any type ofimaging system that emits a beam that is captured by a detector togenerate an image. In one embodiment, imaging system is an X-ray imagingsystem with an emitter 104 including an X-ray source having an X-raytube having an anode, a cathode and a power source, and an X-raydetector. In another embodiment, imaging system is a terahertz imagingsystem having a source emitting electromagnetic waves in the terahertzrange and a cooperating detector. In a further embodiment, the sourcecan provide ultrasonic waves for an ultrasound-based imaging system. Inanother embodiment, system can utilize magnetic resonance imaging,wherein the magnetic source is located inside the emitter gun.

Imaging and alignment systems as described herein can be used with anumber of medical procedures. Various procedures that can advantageouslyutilize such a system will be described below. However, the proceduresdescribed herein are illustrative and are not limiting. System can beused with any medical procedure that would benefit from the use ofimaging. In addition, imaging/alignment systems as described herein canbe employed in non-medical applications. System can be utilized in anynon-medical application that utilizes imaging, such as, for example,airport screening. In such embodiments, system can optionally beprovided with various safety features to prevent human exposure to thebeam, such as not allowing the emitter to emit a beam when it is notaimed at the detector and ceasing emission if it is detected that humantissue or bone is within the imaging field. In one embodiment, imagerecognition can be employed to detect whether safety features should beinvoked.

In one embodiment, imaging system is used to insert pedicle screws intoa spine of a patient. Emitter gun can be equipped with a drill bit anddrive assembly for inserting the screws into the pedicle and optionallydrilling pilot holes into the pedicles prior to insertion. In pediclescrew insertion, it is key to align the screws axially down the pedicle.However, the pedicles are often not aligned perpendicular to thedetector and each pedicle may have a different alignment. Use of imagingsystem allows an accurate image of each pedicle to allow the screws tobe properly placed axially along the pedicles.

In another embodiment, imaging system can be used to aid in performingneedle biopsies. The actuator in such a system can be be a needle, whichcan be translucent. Imaging system allows the surgeon to view anaccurate real-time image of where the needle is positioned to ensurethat the biopsy is taken in the proper area. In one embodiment, thebiopsy procedure can be a bone biopsy.

In a further embodiment, imaging system can assist vertebroplasty andkyphoplasty procedures. Vertebroplasty uses a hollow needle to injectbone cement into fractured, crushed or otherwise weakened vertebrae toprovide support and treat pain. In kyphoplasty, a balloon is firstinserted into the area through a needle and expanded in the fracture andthen bone cement is inserted into the balloon with the needle. Imagingsystem can be used to properly guide the process with a needle as theactuator for inserting the bone cement and/or balloon.

A number of bones in the body can have fractures repaired usingintramedullary rods. A hole is drilled down the long axis of the boneand a rod is then driven into the cavity to align the bones and promotehealing. The rods can then be locked by drilling screws orthogonallyinto the rod to prevent collapse or rotation. An imaging system asdescribed herein can aid in proper alignment and placement of one ormore of the rod or the locking screws.

In another embodiment, imaging system can be used with a pelvic fixationprocedure. Pelvic fixation is a difficult procedure involving theplacement of plates and/or screws to hold together portions of afractured pelvis. The enhanced imaging of imaging system could beadvantageously used to drill holes in the proper locations and insertthe screws to ensure that the screws properly engage the complicatedstructure of the pelvic bones.

In a further embodiment, imaging system can be used to aid in resectingbones, such as knee bones. Emitter could be equipped with a saw blade,milling tool, or other device for removing bone. The system could thenbe used to enhance the visualization of a minimally invasive procedureto ensure that the bone is resected at the proper angle and depth.

In one embodiment, a second emitter and detector plate can be utilizedin the system, which can be positioned at a known offset from thosealready present in the system. By using this second imaging set to imagethe same target area, a three-dimensional stereoscopic image of theprocedure can be generated. Such an imaging system can provide a senseof depth to the procedure that can allow a surgeon to see, for example,how far a drill has penetrated into a bone or how far a biopsy needlehas been inserted. In one embodiment, the separate emitter and detectorcan be provided by a traditional c-arm device. Alternatively, the secondemitter can be a second manually positionable detector as describedherein.

In another embodiment, structured infrared light combined with computerscanning can be incorporated into system to provide a topological viewof the body's surface. This technology can be incorporated into theemitter gun to produce a combined image that shows transparent surfacedetail overlaid onto the image of the underlying bone. This also can beused to provide a sense of drill, needle, or other actuator depth to thesurgeon.

In a further embodiment, a dye injection or spatter mechanism can beintegrated with the emitter gun. The surgeon can then use the gun toinject radiopaque dye ahead of the actuator, allowing a clearer image ofthe target area where the operation is performed. In one embodiment,this procedure can be used in a target area having soft-tissue that doesnot normally image well under imaging beam, such as in various biopsytypes.

Various embodiments of systems, devices and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the present invention. It should beappreciated, moreover, that the various features of the embodiments thathave been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions,shapes, implantation locations, etc. have been described for use withdisclosed embodiments, others besides those disclosed may be utilizedwithout exceeding the scope of the invention.

1. A medical imaging and alignment system for use in performing amedical procedure on a patient, comprising: a manually positionable beamemitter adjustable in more than three degrees of freedom, the emitterincluding an actuator for performing the medical procedure along an axisof operation; a generally planar detector that detects a beam from theemitter, the beam oriented along an axis parallel to the axis ofoperation of the actuator, and generates an original image of a regionof interest between the detector and emitter; a position monitoringsystem that monitors a position and an orientation of the emitter in themore than three degrees of freedom; a processor operably connected tothe position monitoring system and the detector and configured toexecute an image correction algorithm, the image correction algorithmoperable to provide a corrected image from the original image, theoriginal image of the region of interest skewed when the axis alongwhich the beam is emitted is at an angle that is not perpendicular tothe detector relative to an actual appearance of the region of interestfrom the angle and the corrected image showing the actual appearance ofthe region of interest from the angle; and a video display that displaysthe corrected image in real-time to a surgeon performing the medicalprocedure on the patient.
 2. The system of claim 1, wherein the imagecorrection algorithm operates directly on texture coordinates of theoriginal skewed image recorded by the detector using matrix transforms.3. The system of claim 1, wherein the image correction algorithmutilizes rasterization to provide the corrected image.
 4. The system ofclaim 1, wherein the position monitoring system is a kinematic ormechanical tracking system.
 5. The system of claim 4, wherein theemitter is connected to an arm of the kinematic or mechanical trackingsystem.
 6. The system of claim 1, wherein the position monitoring systemis an optical tracking system.
 7. The system of claim 1, wherein theemitter is manually positionable in at least 5 degrees of freedom. 8.The system of claim 1, wherein the position monitoring system is atleast partially located within the emitter.
 9. The system of claim 1,wherein the actuator is selected from the group consisting of a drill, acutting blade and a needle.
 10. The system of claim 1, wherein the axisof operation of the actuator and the axis along which the beam isemitted are coaxial.
 11. The system of claim 10, wherein at least aportion of the actuator that is coaxial with the axis along which thebeam is emitted is formed of a material that is translucent to the beam.12. The system of claim 1, wherein the emitter is an X-ray emitter andthe detector is an X-ray detector.
 13. A method comprising: providing asystem for performing a medical procedure on a patient, the systemcomprising: a manually positionable beam emitter adjustable in more thanthree degrees of freedom, the emitter including an actuator forperforming the medical procedure along an axis of operation; a generallyplanar detector that detects the beam from the emitter, the beamoriented along an axis parallel to the axis of operation of theactuator; a position monitoring system that monitors a position and anorientation of the emitter in the more than three degrees of freedom; aprocessor operably connected to the position monitoring system anddetector that is configured to execute an image correction algorithm;and a video display; and providing instructions for using the system toperform the medical procedure on the patient, the instructionscomprising: manually positioning the emitter in more than three degreesof freedom and generating an original image of a region of interest ofthe patient with the detector, the emitter being aligned along the axisof operation of the actuator at an angle that is not perpendicular tothe detector resulting in the original image being skewed relative to anactual appearance of the region of interest from the angle; viewing acorrected image of the region of interest on the video display showingthe actual appearance of the region of interest from the angle, thecorrected image resulting from application of the image-correctionalgorithm to the skewed original image; and performing the medicalprocedure on the patient using the actuator along the axis of operationwhile viewing the corrected image on the imaging system in real-time.14. The method of claim 13, wherein the step of manually positioning theemitter includes moving the emitter and an arm of a kinematic ormechanical tracking system to which the emitter is attached.
 15. Themethod of claim 13, wherein the step of manually positioning the emitterin more than three degrees of freedom includes manually positioning theemitter in at least five degrees of freedom.
 16. The method of claim 13,wherein the emitter is an X-ray emitter and the detector is an X-raydetector.
 17. The method of claim 13, wherein the step of performing themedical procedure includes inserting a needle that comprises at least aportion of the actuator into the region of interest.
 18. The method ofclaim 13, wherein the step of performing the medical procedure includesutilizing a drill assembly that comprises at least a portion of theactuator to drill into the region of interest.
 19. The method of claim13, wherein the step of performing the medical procedure includesresecting a bone with at least a portion of the actuator.
 20. A systemfor performing a medical procedure on a patient comprising: means foremitting a beam, the means for emitting being manually positionable inmore than three degrees of freedom and including a means for performinga medical procedure on a patient along an axis of operation; means fordetecting a beam from the emitter, the beam emitted along an axisparallel to the axis of operation of the means for performing a medicalprocedure, and generating an original image of a region of interestbetween the means for emitting and the means for detecting; means forgenerating data representative of the position and orientation of themeans for emitting in the more than three degrees of freedom; processingmeans operably connected to the means for detecting and the means forgenerating data representative of the position and orientation of themeans for emitting, the processing means configured to execute a meansfor providing a corrected image from the original image, the originalimage of the region of interest skewed when the means for emitting is atan angle that is not perpendicular to the means for detecting relativeto an actual appearance of the region of interest from the angle and thecorrected image showing the actual appearance of the region of interest;and means for displaying the corrected image in real-time to a surgeonperforming the medical procedure on the patient.
 21. The system of claim20, wherein the means for providing a corrected image executed by theprocessing means operates directly on texture coordinates of theoriginal skewed image detected by the means for detecting using matrixtransforms.
 22. The system of claim 20, wherein the means for providingthe corrected image executed by the processing means utilizesrasterization to provide the corrected image.
 23. The system of claim20, wherein the means for generating data representative of the positionand orientation of the means for emitting is a kinematic or mechanicaltracking system.
 24. The system of claim 23, wherein the means foremitting is connected to an arm of the kinematic or mechanical trackingsystem.
 25. The system of claim 20, wherein the means for generatingdata representative of the position and orientation of the means foremitting is an optical tracking system.
 26. The system of claim 20,wherein the means for generating data representative of the position andorientation of the means for emitting is at least partially locatedwithin the means for emitting.
 27. The system of claim 20, wherein themeans for emitting is manually positionable in at least five degrees offreedom.
 28. The system of claim 20, wherein the axis of operation ofthe means for performing the medical procedure and the axis along whichthe beam is emitted are coaxial.
 29. The system of claim 28, wherein atleast a portion of the means for performing the medical procedure thatis coaxial with the axis along which the beam is emitted is formed of amaterial that is translucent to the beam.
 30. The system of claim 20,wherein the means for emitting a beam emits X-rays and the means fordetecting a beam detects X-rays.